STRATIFIED CHARGE FOUR-STROKE ENGINE

MOTEUR A QUATRE TEMPS A CHARGE STRATIFIEE

English Abstract

ABSTRACT OF DISCLOSURE
Disclosed herein is an internal combustion
engine comprising a cylinder, a piston movable in the
cylinder between top dead center and bottom dead cen-
ter positions, and an air entry port located in the
cylinder adjacently above the piston when the piston
is at bottom dead center and adapted to be opened and
closed in response to piston movement, which air entry
port extends generally tangentially from the cylinder
so that air entering the cylinder through the port
swirls within the cylinder, together with valve means
preventing flow from the cylinder and permitting flow
into the cylinder.

Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined
as follows:
1. An internal combustion engine comprising
a cylinder, a piston movable in said cylinder between
top dead center and bottom dead center positions, an air
entry port located in said cylinder adjacently above
said piston when said piston is at bottom dead center and
adapted to be opened and closed in response to piston movement,
said entry port being arranged in angularly extending
generally tangentially relation to said cylinder so that
air entering said cylinder through said port swirls within
said cylinder, an air chamber extending at least partially
circumferentially around said cylinder and communicating
with a source of air and with said air entry port, and a
reed valve operatively associated with said port for prevent-
ing flow from said cylinder to said air chamber and permitting
flow into said cylinder from said air chamber.
2. An internal combustion engine in accordance
with Claim 1 wherein said source of air comprises means for
providing a pressurized flow of air.
3. An internal combustion engine in accordance
with Claim 1 wherein said engine is a four-stroke engine.
4. An internal combustion engine in accordance
with Claim 3 wherein said cylinder includes a head end
spaced from said piston when said piston is at bottom
dead center and further including a main inlet port adjacent
said head end of said cylinder, and means for closing said
main inlet port as said piston approaches bottom dead
center.

5. An internal combustion engine comprising a
cylinder, a piston movable in said cylinder between top
dead center and bottom dead center positions, a plurality
of air entry ports located in the cylinder adjacently
above said piston when said piston is at bottom dead
center and adapted to be opened and closed in response to
piston movement, said air entry ports being arranged around
said cylinder in an angularly spaced series and extending
generally tangentially from said cylinder so that air
entering said cylinder through said ports swirls within
said cylinder, an air chamber extending at least partially
circumferentially around said cylinder and communicating
with a source of air and with said plurality of said air
entry ports, and a separate reed valve operatively associated
with each of said ports for preventing flow from said
cylinder to said air chamber and permitting flow into said
cylinder from said air chamber.
6. An internal combustion engine in accordance
with Claim 5 wherein said source of air comprises means for
providing a pressurized flow of air.
7. An internal combustion engine in accordance
with Claim 5 wherein said engine is a four-stroke engine.
8. An internal combustion engine in accordance with
Claim 7 wherein said cylinder includes a head end spaced from
said piston when said piston is at bottom dead center and
further including a main inlet port adjacent said head end
of said cylinder, and means for closing said main inlet port
as said piston approaches bottom dead center.

Description

7Z~50
TITLE
STRATIFIED C~RGE FOUR-STROKE ENGINE
;~ INVENTOR
JOSEF EHRLICH
BACKGROUND OF I~E INVENTION
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, This invention relates to internal combustion
engines and more particularly to four-stroke internal
combustion engines. The invention also relates to
methods and arrangements for effecting stratification and
turbulence in the cylinder of an internal combustion engine.
SUMMARY OF THE INVFNTION
The invention provides an internal combustion
engine comprising a cylinder, a piston movable in the
~, cylinder between top dead center and bottom dead center
positions, an air entry port located in the cylinder adjacently
above the piston when the piston is at bottom dead center
and adapted to be opened and closed in response to piston
movement, which air entry port i9 arranged in generally
tangential relation to the cylinder so that air entering
; 20 the cylinder through the port swirls within the cylinder,
an air chamber extending at least partially circumferen-
tially around the cylinder and communicating with a source
of air and with the air entry port, and a reed valve opera-
tively associated with the port for preventing flow from
the cylinder to the air chamber and permitting ~low into
the cylinder from the air chamber.
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In one embodiment a plurality of the air entry
ports communicate between the cylinder and the air chamber,
are arrang~d around the cylinder in an angularly apaced
series,and extend generally tangentially from the cylinder
so that air entering the cylinder through the ports swirls
within the cylinder, and a separate reed valve is operatively
associated with each of the ports for preventing flow from
the cylinder to the air chamber and permitting flow into the
cylinder from the air chamber.
In one embodiment in accordance with the invention,
the source of air comprises means for providing a pressurised
flow of air.
In one embodiment in accordance with the invention,
the engine is a four-stroke engine.
In one embodiment in accordanc~ with the invention,
- the cylinder includes a head end spaced from the piston when
` the piston is at bottom dead center and further including a
main inlet port adjacent the head end of the cylinder, and means
for closing the main inlet port as the piston approaches
bottom dead center.
Other features and advantages of ,the embodiments of
the invention will become known by reference to the following
general description, appended claims and attached drawings.
I~IE DRAWINGS
Figure 1 is a sectional elevation of an engine
embodying the invention.
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Figure 2 is a sectional view taken along
lines 2--2 in Figure 1.
Before explaining the embodiments of the
invention in detail, it is to be understood that the
invention is not limited in its application to the
details of the construction and arrangement of parts
set forth in the following general description or
illustrated in the accompanying drawings, since the
invention is capable of other embodiments and of being
practiced or carried out in various ways. Also, it is
to be understood that the phraseology or terminology
employed herein is for the purpose of description and
not of limitation.
GENERAL DESCRIPTION
Figure 1 shows how when the piston 11 is
approaching bottom dead center (it is shown in Figure
1 at bottom dead center) the last movement of the
piston on the inducation stroke draws air into the
cylinder 12 through ports 13 arranged circumferentially
around the cylinder wall. Figure 2 shows that there
are three ports 13 arranged circumferentially around
the cylinder wall, and communicating with a surro~mding
chamber or gallery 14 connected to a source of air
at 15 which may merely be the surrounding air or may
be ~h~e outlet from a means for providing a pressurized
flow of air such as a pump driven by the engine. Each
` port 13 is fitted with a reed valve 16 permitting air
to enter the cylinder when there is a pressure differ-
ential across it but preventing gas from escaping from
the cylinder.
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The main fuel-air inlet valve 17 is arranged to
be closed by its cam 18 as the ports 13 begin to be
uncov~red.
On the induction stroke the piston draws in
fuel/air mixture through the port 17 which is closed as the
piston appraoches bottom dead center and starts to uncover
the air ports 13. Thus the final movement of the piston
draws air in through the ports 13 and their reed valves.
The tangential direction of the ports 13 shown in
Figure 2 causes the incoming air to swirl generally as
indicated at 18 within the cylinder, thus producing strati-
fication and turbulence.
On the compression stroke the reed valves prevent
escape of charge before the ports 13 are covered, and on the
subsequent working stroke,even after the ports are uncovered
as the piston appraoches bottom dead center,the reed
valves 16 will prevent loss of the ignited charge and loss
of pressure.
On the exhaust stroke the burnt products of com-
bustion are discharged through the exhaust valve 19 which issuitably opened by its cam 20.
Various of the features of the invention are
set forth in the following claims.
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